[Live-devel] RTP timestamp vs presentation timestamp inMPEG2 elementary streams

[Jeff Kowing]

Ross Finlayson wrote:

> Yes.  (I presume you're referring to RFC 2250.)  Section 2 of the RFC 
> (that mentions "transmission time for the first byte of the packet") 
> refers to streaming MPEG Transport Streams.  Section 3 of the RFC (that 
> mentions "Presentation Time Stamps") refers to streaming MPEG Elementary 
> Streams.  These are effectively two different RTP payload formats 
> (actually, three, because Audio and Video Elementary Streams also have 
> separate formats) that just happen to be written up in the same RFC.

So, just to clarify (and to make sure I also have this correct):

RTP with payload type 32 (MPEG1/2 video ES): The RTP timestamp 
represents PRESENTATION time of the video frame (thus, multiple RTP 
packets carrying the same video frame will have the same timestamp).

RTP with payload type 33 (MPEG2 TS): The RTP timestamp represents 
TRANSMISSION time of the RTP packet.

While on this subject, is there any reason I should choose the MPEG2 TS 
payload type over the MPEG1/2 video ES payload type if I just want to 
stream live output from video cameras?  Are there any advantages to one 
over the other?

-- 
Jeff Kowing